Photographic drier



April 10, 1951 I w SAUTER 2,548,824

IIHOTOGRAPHIC DRIER Filed April 23, 1948 Ifgi. d

IN VEN TOR.

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Fatented Apr. 10, 1951 PHOTOGRAPHIC DRIER Oscar William Sauter,Glendale, Calif., assignor to The H. I. Thompson Company, Los Angeles,Calif., a corporation of California Application April 23, 1948, SerialNo. 22,761

3 Claims.

This invention relates to improvements in the construction of driers forphotographic prints.

Qne form of drier employs an endless belt which passes over a rotatableheated drum. The prints are placed between the belt and the drum and asthe belt travels over the drum the prints are brought into contact withthe heated drum and thus heated.

In such operations, the moisture must be removed from the surface of thepaper and caused to evaporate through the belt. It is most important toprevent accumulation of water between the print and the belt. Theevaporation of such moisture from a droplet of water held between theprint and the belt will cause blistering of the print.

The prior art attempted to solve these two requirements of porous beltand prevention of accumulation of water droplets between the belt andthe print by the following expedients: The

belt was made porous and water absorbent by employing a belt formed ofwoven straw matting covered with light canvas. It was found necessary inorder to minimize the possibility of blistering that care be used todrain the washed prints thoroughly, and when excessively wet they mustbe pre-dried between blotters before placing them on the belt.

Such belts readily became soiled and stiii .due to the accumulation ofsalts resulting from the evaporation of the water, which salts are theresults of the developer not completely removed by washing. The saltsalso attack the belt chemically and weaken and impair its utility. Thebelt must therefore be frequently replaced. In some busy laboratoriesthis may be as often as twice a day.

Additionally. the belts become charred and burn if the drier is stoppedwhile the drum is hot. In shutting down the machinery the heatingelement mounted in association with the drum must first be shut off andthe machine run until the drum cools down. This takes at least ten tofifteen minutes. It also takes an equal time to heat the drum again.

The above considerations also limit the temperature at which the drummust be operated and the tension which it is permissible to place on thebelt. The belt is of such mechanical construction that it may not beplaced in high tension and since it is usually soon stiff with salts andimpaired in quality it may not be stressed too greatly. Additionally, itbecomes saturated with moisture and becomes slack. Because of thelimitation in tension and the limitations in the permissibletemperature, it is frequently necessary to run prints through twice tocompletely dry and iron them flat.

I have discovered that I may obviate all of these difficulties byreplacing such prior art belts with a belt formed of woven glass fiberssuitably prepared for this service.

Such woven glass fibers do not have the disadvantages of the prior artbelts. ,They are porous and non-absorbent. The moisture is completelyevaporated from the belt. The belt is not attacked by the salts and maybe readily washed to remove salt incrustations and to keep it clean andporous without removing the belt from the machine. It is resistant tohigh temperatures and is not inflammable or in any way aiiected by heatmuch higher than the boiling point of water and has a high tensilestrength.

Because of these properties this machine may be operated at a higherbelt tension and higher temperature than with the prior art belts, andat a higher speed. Because of the higher temperature and tension, theprints may be passed through but once at even a higher speed and dryflat and produce prints which are dry and flat. This increases thecapacity of the machine.

It is unnecessary to replace belts, since the belts can be kept clean bysimply washing them on the machine, and since they are not attacked bythe salts. Whereas the average life of the belts of the prior art arefrom one week to half a day, depending on the service, one belt of myinvention has been in service for eight months without removal from themachine and without any visible signs of wear or deterioration.Additionally, it is not necessary to allow the machine to cool downbefore stopping the belt. It is possible to stop the belt while the heatis on the drum. This cuts down the down-time required to cool and reheatthe drum and increases production. An important consideration is thatthere is no fire hazard. With the prior art belts, if the belt isstopped before the drum cools down, the belt may catch on fire-anaccident which has happened with sufiicient frequency to make the priorart belt a fire hazard.

I have thus found that by substituting a belt of my construction for theprior art belt, I have:

(a) Increased the productive capacity of the machine; J

(b) Avoided the necessity for frequent replacement of the belt;

(c) Made possible the drying and ironing of the prints in a single passinstead of two passes;

Fig. 5 is a section taken on line 5-5 of Fig. 3.

The drum support 2 positioned on each side of the drum 3 is mounted onbase I. The drum 3 is mounted, on trunnions and stub shaft 4, in support2. The drum is hollow and heater 5, which may be an electricalresistance heater or a gas flame, is mounted through one of thetrunnions 4 and suitably connected to a current source or a gas line asthe case may be. Mounted on support 2 are the idler belt shafts 6, l,and 8. A shaft 9 is also mounted on the support 2. Each of the shafts 6,l, 8, and 9 carries a sprocket over which the sprocket chain [9 ispassed. The shaft 9 is driven through gear box I3, pulley and beltassembly 12 by the motor ll.

Mounted in base I is an extension bracket lila. Idler shafts l5 and I6are mounted on the extension !3a and idler shaft I4 is mounted on thebase I. Mounted on the support 2 is a receiving pan I1 and a plate 18. Abelt I9 is threaded over shafts 6, 1, 8 and 15. The belt extends to forma substantiaily horizontal section or apron extending from the shaft i5and becoming tangent to the drum, passing over the drum and underneathshafts 9, l9, and I4 and over the drum 3.

In order to dry and iron the prints, the prints are laid on the belt(but not at the point shown in Fig. 3) in front of the pan l1 and as thebelt travels the prints pass between the belt and the heated drum andare picked up by the blade 49 and deposited in the pan 11.

In the drier of my invention I employ a belt of woven glass fiber,preferably woven with a crows foot pattern. The belt is coated for adistance of about one inch on both sides of the belt at 29 and 2i at theselvedge edges and at 22 of each of the cut edges of the strip 23 whichis to be formed into the belt. The glass cloth is acid resistant (exceptto hot phosphoric and hydrofiuoric acids) and is non-hygroscopic andwill not stretch nor shrink due to wetting and drying and will resisttemperature far in excess of the maximum temperature attained in thedrier.

I may employ dry adhesive coating such as rubber latex or any elastomerlatex such as the iii) 12 ounce canvas strip 24, folded over on each endand sewn with a synthetic fiber such as that of the polyamine type infour separate seams 24a; and joined together with a waxed cord 25 bymeans of a baseball stitch. In using the belt it is desirable not toplace the prints at the joint, nor to stop the machine with the jointnext to the drum.

While I have described a particular embodiment of my invention for thepurpose of illustration, it should be understood that variousmodifications and adaptations thereof may be made within the spirit ofthe invention as set forth in the appended claims.

I claim:

1. A belt formed of a strip of woven glass fibers having an outer glassfiber surface and selvedge edges and cut edges, each of said edges beingadhesively coated with a dry adhesive, the coated out edges beingcoveredwith light canvas and joined by a thread stitch at said edges into anendless belt.

2. A drier for photographic film comprising a drum, means for heatingsaid drum, a standard upon which said drum is rotatably mounted, a basefor said standard, a plurality of belt shafts on said base and standard,a belt formed of a strip of woven glass fibers having selvedge edges andcut edges, each of said edges being adhesively coated with a dryadhesive, the coated cut edges being covered with light canvas andjoined by a thread stitch at said edges into an endless belt, andthreaded over said shafts to form a horizontal belt upon and passingtangent to said drum and over said drum, means for moving said belt oversaid drum, and means for rotating said drum.

3. A drier for photographic film comprising a drum, means for heatingsaid drum, a standard upon which said drum is rotatably mounted, a basefor said standard, a plurality of belt shafts on said base and standard,an endless belt formed of a strip of woven glass fibers, said belthaving an outer glass fiber surface and selvedge edges, said selvedgeedges being coated with dry adhesive, said belt being threaded over saidshafts and said belt passing over said drum; and means for moving saidbelt over said drum and for rotating said drum.

0. WILLIAM SAUTER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 355,766 Kenyon Jan. 11, 18871,384,125 Dye July 12, 1921 1,635,185 Kimmich July 12, 192'? 1,944,600Greene Jan. 23, 1934 2,135,057 Slayter et a1 Nov. 1, 1938 2,179,691Freedlander Nov. 14, 1939 2,360,257 Muller et a1 Oct. 10, 1944 2,446,294Mitchell Aug. 3, 1948

